The principal type of indwelling bladder catheter is the "Foley" which has a balloon on the bladder end. After the Foley catheter is inserted in the bladder, the balloon is inflated (with air or fluid) so that the catheter cannot pull out but is retained in the bladder as an indwelling catheter. Removal is accomplished simply by deflating the balloon and slipping the catheter out. The "Foley" is named for Frederic Eugene Basil Foley (1891-1966), an American urologist.